Ileostomy is the main cause of complications in the surgical treatment of chronic, nonspecific ulcerative colitis. The principal complication is ileostomy dysfunction (obstruction) in the immediate postoperative period. The importance of this complication cannot be overemphasized. In a review of 210 patients undergoing ileostomy, Warren and McKittrick1reported that 62% of their patients had dysfunction. Of 37 deaths in that series, were attributed to dysfunction of the ileostomy and its sequelae and 3 others were thought to have been possibly related to ileostomy dysfunction. The number of deaths from ileostomy dysfunction was second only to the number of deaths from peritonitis. Today, with the decreasing incidence of fatal postoperative peritonitis, it would appear that the ileostomy itself constitutes the primary postoperative hazard. Our experiences with the ileac stoma have led us to believe that the construction of the conventional ileostomy violates a fundamental surgical principle, i. e., the vulnerable serosa of the ileostomy is left exposed. Inflammatory changes in the projecting ileostomy are